1- The GDT contract?We don't know the details, but it was originally for 3 years, which are almost up, and still no start date. Who knows how much longer it will be?

2- The Hobbit is not so important to GDT to wait a little more?It isn't "a little", it's some unknown number of years more, and as others have noted, he has other commitments that he cannot ignore without destroying his reputation.

3- Perhaps he now somethig about the all hobbit movie that we don´t now, ex: there is no Hobbit movieWell, a great deal of work has been done by a lot of people assuming it will happen, even in the absence of a formal "green light" to the project. The studios know that this movie has the potential to make a great deal of money, which the studios desperately need.

4- The leaving of GDT puts PJ in a dificult position to all people involved, GDT don't care?I'm sure it's because he does care that he stuck with the project so long in spite of the delays.

5- He simple leave the place?He has said he would stay long enough to help with the scripts. The scripts are theoretically finished; I assume this means help with revisions that may become necessary (as is always the case).

6- They left behind is "drawing book"?A good deal more than that, I think. Thousands of designs, models of creatures, all the work that's been done at Hobbiton (documented by photos here on TORn), many man-years of effort at this point. And the scripts too, of course.

7- In movie business all people involved now that the delay in the production is "normal"Delays do happen. Some are more serious than others. In this case, a studio that owns half the rights to the picture is in extreme financial and legal difficulty. That's a lot worse than the usual delays.

8- Think: If hapenned a little "tragedy" during the shooting, like great rain and for that reason they have to wait 3 or 6 months, he leave the movie??? Those are the sorts of delays that commonly occur in films. LotR suffered several such problems. Usually the response is to shift the schedule to parts of the project that the "tragedy" doesn't directly affect. As I noted above, the MGM problem is much more serious. Whether there are other difficulties as well, we do not know.